This is a revision of Program Project proposal 1 PO1 HD-047609 "Gene-Environment Interactions in Human Parturition" that was submitted in October 2003, reviewed by an NICHD Special Emphasis Panel, and received a priority score of 199 (30th percentile). In this research program we proposed to identify the genetic and env/ronmenfa/ determinants of the length of human gestation/ timing of onset of spontaneous parturition, and to model the gene, environment, and maternal-fetal interactions that may underlie the risk of premature birth among three racial/ ethnic populations: African-Americans, Hispanics and nonHispanic Whites. The previous review commented favorably on all aspects of the Administrative Core as proposed, and determined that overall the Core appears appropriate and should be able to meet its functions. The review did not raise any concerns about the Core.